103 



TABLES FOR RETRACTION. 



Table 1. 



Table 2, Barometer. 



Logarithm in Tab. I. + log. barom. + log. tan. zenith dist. = log. ap- 

 proximate refraction. 



i\ppr. ref. — Number Tab. 2. = refraction. 



Example. Zenith dist. 71°. 26', barom. 29,76 inches and therm. 4S°. 



Log. Tab. 1 



Log. barom. -'^ 



Log. tan. 7 1 ".26 



Ref. 173,4 =:2'.53",4 



Log. approx. ref. 175"4 - 2.2439 



0.2965 

 1.4736 

 0.4-738 



Appi'. ref. 175' ',4 

 Tab. 2. 2, 



